The research proposed here is designed to contribute to an understanding of the function of the primate craniofacial region. Functionally the primate craniofacial region is dominated by the masticatory apparatus. This research will analyze how masticatory forces are dissipated throughout the primate face. This in vivo analysis of strain in the facial bones of Macaca fascicularis will be accomplished using strain gauges. Rather than using single-element strain gauges, rosettes (three strain gauge elements with a known orientation to one another) will be bonded directly to facial bones with methyl-3-cyanoacrylate. The restrained macaque will then bite a transducer or chew various types of foods and bone strain will be recorded on a multichannel chart recorder. In order to precisely correlate the animal's behavior with patterns of bone strain, the animal and the chart recorder will be videotaped. With a special effects generator, a split screen display of both animal and recorder will be produced and recorded.